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 // Copyright ©2015 The Gonum Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package testlapack import ( "testing" "golang.org/x/exp/rand" ) type Dgebd2er interface { Dgebd2(m, n int, a []float64, lda int, d, e, tauq, taup, work []float64) } func Dgebd2Test(t *testing.T, impl Dgebd2er) { rnd := rand.New(rand.NewSource(1)) for _, test := range []struct { m, n, lda int }{ {3, 4, 0}, {4, 3, 0}, {3, 4, 10}, {4, 3, 10}, } { m := test.m n := test.n lda := test.lda if lda == 0 { lda = n } // Allocate m×n matrix A and fill it with random numbers. a := make([]float64, m*lda) for i := range a { a[i] = rnd.NormFloat64() } // Store a copy of A for later comparison. aCopy := make([]float64, len(a)) copy(aCopy, a) // Allocate slices for the main and off diagonal. nb := min(m, n) d := nanSlice(nb) e := nanSlice(nb - 1) // Allocate slices for scalar factors of elementary reflectors // and fill them with NaNs. tauP := nanSlice(nb) tauQ := nanSlice(nb) // Allocate workspace. work := nanSlice(max(m, n)) // Reduce A to upper or lower bidiagonal form by an orthogonal // transformation. impl.Dgebd2(m, n, a, lda, d, e, tauQ, tauP, work) // Check that it holds Qᵀ * A * P = B where B is represented by // d and e. checkBidiagonal(t, m, n, nb, a, lda, d, e, tauP, tauQ, aCopy) } }